"Why this recipe works:The key to Angel Food Cake is voluminous, stable egg whites. A mere speck of yolk precludes them from whipping to peaks. We had the best success with either cold or room-temperature egg whites. Cold whites whipped to the same volume as room-temperature eggs (they just took a few minutes longer). Cream of tartar offered some insurance against deflated whites. Its acidity helped stabilize the egg whites...."